Minimum size of a UFS partition

[illoai at gmail.com]

On 4 December 2013 05:53, Erich Dollansky <erichsfreebsdlist at alogt.com> wrote:
> Hi,
>
> On Wed, 4 Dec 2013 11:15:41 +0100
> Polytropon <freebsd at edvax.de> wrote:
>
>> On Wed, 4 Dec 2013 15:59:07 +0800, Erich Dollansky wrote:
>> > Hi,
>> >
>> > does anybody know how small a partition for UFS can get?
>> >
>> > I would need a very small partition of even below 1.44 MB.
>>
>> That should be possible by applying specific options to newfs
>
> with the other tip, I came to a size of 1MB for the given application.
>
> Erich

A bit of experimentation:
# mdconfig -s 2048
md0
# newfs -O 1 -b 4096 -f 4096 -i 16384 -s 4 /dev/md0
Filesystem size 0 < minimum size of 8
 # newfs -O 1 -b 4096 -f 4096 -i 16384 -s 40 /dev/md0
Filesystem size 5 < minimum size of 8
# newfs -O 1 -b 4096 -f 4096 -i 16384 -s 64 /dev/md0
/dev/md0: 0.0MB (64 sectors) block size 4096, fragment size 4096
        using 1 cylinder groups of 0.03MB, 8 blks, 32 inodes.
super-block backups (for fsck_ffs -b #) at:
 32
first cylinder group ran out of space
# newfs -O 1 -b 4096 -f 4096 -i 16384 -s 80 /dev/md0
/dev/md0: 0.0MB (80 sectors) block size 4096, fragment size 4096
        using 1 cylinder groups of 0.04MB, 10 blks, 32 inodes.
super-block backups (for fsck_ffs -b #) at:
 32
first cylinder group ran out of space
# newfs -O 1 -b 4096 -f 4096 -i 16384 -s 96 /dev/md0
/dev/md0: 0.0MB (96 sectors) block size 4096, fragment size 4096
        using 1 cylinder groups of 0.05MB, 12 blks, 32 inodes.
super-block backups (for fsck_ffs -b #) at:
 32

So, the answer is: pretty small!

Cheers.

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